Hydraulic air compressor



At)! 20, 1937. J JONES ET AL 2,077,482

HYDRAULI C AIR COMBRES SOR Original Filed Nov. 19, 1934 '1 mm A UTTOGTJOTS JEJones R.J. Unswor-Hw Patented Apr. 20, 1937 UNITED STATES PATENT HYDRAULIC AIR COMPRESSOR John E. Jones, Toronto, Ontario, and Robert J. Unsworth, Niagara Falls, Ontario, Canada 14 Claims.

This invention relates to hydraulic air compressors. Hydraulic air compressing plants of the type in which water under head due to difference in levels, flows down a tube or penstock,

entraining air at its entrance and discharging into a closed tank at the bottom, from which the air is conveyed to storage and the water discharged to a tail race, are well known in the art. Nature restricts their location, however to a source of running water adjacent to a lower contour of ground. However, this principle of compressing air has advantages over the ordinary reciprocating piston or rotary pump method of compressing air in that there are few moving parts, the compressed air is free from dirt or other foreign matter and comparatively dry, and the compression is isothermal.

The main object of our invention is to produce an apparatus which will use the principle of entraining air in falling water or other liquid but which will not require a source of running water or a great head of Water or other liquid. Another object is to provide a penstock which will efficiently entrain the air and which will discharge the mixture of airand water in such a way as to quickly and effectually separate the air from the water.

Our invention is hereinafter described and i1- lustrated in the accompanying drawing in which Fig. 1 is a diagrammatic vertical sectional view of one unit and part of a second unit of our air compressing apparatus.

Fig. 2 a cross section of the penstock and the air inlet pipe on the line 2-2 in Fig. 1, on an enlarged scale,

Fig. 3 a vertical section partly broken away of the penstock showing the outlet end of the air inlet pipe, on the same scale as Fig. 2.

Fig. 4 a bottom plan View of partly broken away; and

Fig. 5 a vertical section of the distributing end of the penstock and of the centrifugal pump on an enlarged scale, the section being taken on the line 5-5 in Fig. 4.

In the drawing corresponding numbers in the different figures refer to corresponding parts.

I represents a closed upper tank and 2 a closed lower or compression tank. A penstock 3 extends from the upper tank I into the compression tank 2 and its lower end is bent within the compression tank through an angle of 180 in a vertical plane, and continued vertically to the discharge end Which is above the normal water level of the water in the compression tank when the the rotary pump device is in operation. The second 90 of the bent or curved portion of the penstock is of less radius than the first 90, which minimizes the accumulation of the air bubbles on the inside of the curve. The discharge end of the penstock is 5 flared outwardly at an angle of substantially While one only penstock 3 is shown and described in the drawing and specification, a plurality of penstocks may be provided each being upwardly curved in the compression tank and 10 converging to form a common vertical discharge end.

Extending through the upper tank I and into the penstock 3 is an air inlet pipe 4 having at its lower end within said pipe 4 a plurality of 15 outwardly and downwardly extending tubes or jets 5. The air discharge portion of the air inlet pipe 4 is cruciform in cross section and the jets 5 extend outwardly and downwardly therefrom from various points throughout the air discharge portion of the said air inlet pipe 4. The jets 5 are so arranged that commencing at the uppermost jet each succeeding adjacent jet is spaced from and slightly below the preceding jet, which arrangement may be conveniently described as spiral. The penstock adjacent the air discharge portion of the air pipe 4 is of enlarged cross-section in order that the net cross-sectional area may not be reduced by the jets 5 and in order to make provision for the increased volume of the mixture owing to the addition to the water of the entrained air.

The air pipe 4 may also be tapered at its discharge end to reduce the cross-sectional area progressively as air is withdrawn through the jets 5. Below the end of the air inlet pipe, the walls of the penstock gradually converge to the point where it enters the compression tank 2 whereby the velocity of the mixture of air and water is gradually and progressively increased. 40

It will be observed that the construction of the air discharge pipe and jets is such as to provide a maximum of even distribution of the air bubbles in water over any horizontal cross-section of the penstock, and a maximum surface for the introduction of the air. The outwardly and downwardly sloping direction of the jets 5 reduces resistance to the flow of water, but the multiplicity of the jets nevertheless is effective to change the laminar flow of the water to a turbid flow, thereby assisting the entraining of the air.

The location of the air discharge is at any predetermined distance below the upper tank I in order to obtain the maximum efficiency in entraining the air, and the location depends upon such factors as the column of solid water above the air discharge, the superimposed air pressure in the upper tank I, and the water area of the penstock.

On the surface of the water in the upper tank I directly above the opening of the penstock is provided a floating grill 6 which serves the purpose of preventing the creation of a vortex and ensuring a solid column of water entering the penstock 3. This floating grill is provided with an opening therein through which passes the air inlet pipe 4, which serves as a vertical guide for the grill 6, which permits it to move up and down but retains it in position above the opening of the penstock.

Inserted in the discharge end of the penstock is an inverted cone I which acts as a spreader. The annular area between the flared end of the pipe and the spreader is the same as the cross sectional area of the pipe below the place where the flare begins,in order not to change the velocity of the mixture. The mixture of air and water traveling around the bent pipe below the discharge end, is apt to separate out, the air tending to hug the inside of the curve and the Water to hug the outside thereof. To facilitate the distribution and mixing of the air and water, the vertical portion of the penstock below the discharge end is rifled with a plurality of spiral guides 8 (shown in Fig. 5) which are connected to the pipe and to the inverted cone 1, serving also to support the latter. The guides 8 also serve to direct the flow of water and air mixture into the blades 9 of the centrifugal pump Ill. The pump II! is operated through the medium of a shaft II by a motor l2 mounted on top of the compression tank 2.

The centrifugal pump I0 comprises an inverted frusto-conical impeller of the same angle as the flare of the end of the penstock, and having backward turned blades on the outer periphery thereof, the crosssection of the channels between blades at their inner ends being greater than at their outer ends.

Since there is a tendency for the air to hug the following face of the blade, a slot I3 is provided through each blade between each channel which permits a fine spray of solid water from the preceding channel to impinge on the air adjacent I the following face of the blade in the succeeding channel. These slots I3 are preferably substantially tangential to the following face of the blades.

The return water pipe I4 extends from a point adjacent the bottom of the compression tank 2 to a point substantially intermediate the top and bottom of the upper tank I, and is preferably of larger cross-sectional area than the penstock so that the velocity of the return water is relatively small. The pressure developed in the compression tank 2 forces the solid water up the return water pipe I4 without the use of a pump or other supplemental mechanical means.

A pressure is maintained in the upper tank I to supplement the hydraulic head resulting from the elevation of said tank, and in order to create and maintain such a pressure an air pipe 2| is provided between the compression tank 2 and the upper part or dome of the upper tank I controlled by a suitable valve 22. The supplementary pressure thus obtained in the upper tank I makes it possible to obtain the equivalent of an increased head of water without an increase in the height of the tank I.

An air outlet pipe I5 extends from the top of the compression tank 2, and the compressed air may be stored or used as desired or carried to another unit of a multi-stage compression apparatus as hereinafter described.

It is the intention that this apparatus as described, should form one unit of a multi-stage compressing apparatus, each unit of which corresponds to the first unit, and in each unit of which air of successively higher pressure is developed. For this purpose, compressed air from the first unit is carried to the second unit, illustrated as I in Fig. 1 and introduced to the water in the penstock 3 through an air inlet pipe 4 similar to the air inlet 3, except that it is connected to the air outlet pipe l5 instead of to the atmosphere. Any desired number of units may be used in order to develop the required pressure of air.

Valves are provided in the penstock, the water return pipe and the air outlet pipe for controlling the same, and a relief valve I6 and I! is provided in the upper tank I and compression tank 2, respectively for relieving excess pressure.

The operation of the device is as follows: Water in the upper tank I falls through the penstock 3 entraining air from the air inlet pipe 4, and is discharged into the compression tank 2. The passage of the water down the penstock 3 is accelerated by the rotary pump I 0 which acts as a choker to prevent reversal of flow and which also serves to discharge the water with a swirling motion into the compression tank 2, where the air separates out and gathers in the top of the tank while the water gathers in the bottom. The pressure in the tank provides a hydraulic head which forces water up the return water pipe I4 into the elevated tank I. The dome or top of the elevated tank I being closed, forms a trap for air, which is compressed. The pressure is brought up to any predetermined pressure by admitting compressed air from the compression tank 2 through the pipe 2!. This pressure adds additional velocity to the water in its fall, and makes it possible to use a much smaller head of water than would otherwise be practical. The compressed air which gathers in the compression tank 2 is drawn oil through the air outlet pipe I5, or is carried to the next unit of the apparatus.

In order to utilize the energy resulting from the velocity of the discharge of the mixture of air and water from the rotary pump, a turbine l8 (shown in Fig. 5) may be mounted above the pump with its blades adjacent to but spaced from the discharge end of the pump blades 9. The turbine blades are spaced from the pump blades a sufficient distance to permit the major portion of the air to separate from the water before the water strikes the turbine blades. The turbine I8 is mounted on a suitable bearing I9 which is freely rotatable on the shaft ii so that it may rotate freely relative thereto and is geared to a shaft 20 which may be used as a source of power for any desired purpose.

It should be understood that other liquids will be the mechanical equivalent of water in the apparatus described and claimed.

What we claim as our invention is:

l. A hydraulic compressing apparatus comprising an upper tank adapted to contain water, which forms a head; a lower closed compression tank; a penstock extending from the upper tank into the compression tank; means for admitting air to the penstock; a centrifugal pump at the end of the penstock adapted to supplement the effect of the head of water in the upper tank in causing the mixture of air and water to flow down the penstock and discharge into the compression tank; a return water pipe from the compression tank to the upper tank; and an air outlet from the compression tank.

2. A hydraulic compressing apparatus comprising a closed upper tank; a lower closed compression tank; a penstock extending from the upper tank to the compression tank; means communicating directly between a source of air supply and the interior of the penstock for admitting air thereto; a returnwater pipe from the compression tank to the upper tank, the upper tank forming a substantially air tight closed space or dome above the opening of the penstock, adapted to contain air under pressure; means for returning water to the upper tank through the return water pipe; and an air outlet for the compression tank.

3. A hydraulic compressing apparatus comprising a closed upper tank; a lower closed compression tank; a penstock extending from the upper tank to the compression tank; means communicating directly between a source of air supply and the interior of the penstock for admitting air thereto; a return water pipe from the compression tank to the upper tank, the upper tank forming a substantially air tight closed space or dome above the opening of the penstock, adapted to contain air under pressure; means for returning water to the upper tank through the return water pipe; an air outlet for the compression tank; and a valve controlled air conduit adapted to carry compressed air to the upper tank.

4. A hydraulic compressing apparatus comprising a closed upper tank; a lower closed compression tank; a penstock extending from the upper tank into the compression tank, said penstock having an air inlet pipe extending through but not communicating with the upper tank and into the penstock and having a plurality of air outlets opening into the penstock; a Water outlet from the compression tank; means for providing a head of water in the upper tank; and an air outlet from the compression tank.

5. A hydraulic compressing apparatus comprising a closed compression tank; a penstock extending into the compression tank; an air inlet pipe having the upper end thereof open to the atmosphere and extending within and axially of said penstock, the lower end thereof being provided with a plurality of rows of outwardly and downwardly projecting air outlet jets opening into the penstock; a water outlet from the compression tank; means for supplying water to the penstock; and an air outlet from the compression tank.

6. A hydraulic compressing apparatus comprisingaclosedcompression tank; a penstock extending into the compression tank; an air inlet pipe having the upper end thereof open to the atmosphere and extending axially through the penstock and the lower end thereof having a plurality of air outlets opening into the penstock, said penstock being of enlarged cross-section adjacent the said air outlets; a Water outlet from the compression tank; means for supplying water to the penstock; and an air outlet from the compression tank.

7. A hydraulic compressing apparatus comprising a closed compression tank; a penstock extending into the compression tank, the lower end of said penstock being curved to discharge upwardly in said compression tank, the end of said penstock being above the normal operating level of the water in the compression tank; means for admitting air to the penstock; a pump mounted on the said upwardly curved end of the penstock and adapted to accentuate the flow of the mixture of air and water down the penstock and discharge it into the compression tank; a water outlet from the compression tank; means for supplying Water to the penstock; and an air outlet from the compression tank.

8. A hydraulic compressing apparatus, comprising an upper tank; a lower closed compression tank; a penstock extending'from the upper tank into the compression tank, the end of said penstock being outwardly flared; means for admitting air to the penstock; an inverted conical spreader mounted in said outwardly flared portion of the penstock; a centrifugal pump mounted in the compression chamber and having its blades disposed opposite the discharge opening in the end of the penstock; a return Water pipe from the compression tank to the upper tank; and an air outlet from the compression tank.

9. A hydraulic compressing apparatus comprising a closed compression. tank; a penstock extending into the compression tank, the lower end of said penstock being curved to discharge upwardly in said compression tank, the upwardly directed end part of the penstock being provided with curved guides; means for admitting air to the penstock; a water outlet from the compression tank; means for supplying water to the penstock; and an air outlet from the compression tank.

10. A hydraulic compressing apparatus, comprising an upper tank; a lower closed compression tank; a penstock extending from the upper tank into the compression tank, the end of said penstock being outwardly flared; means for admitting air to the penstock; an inverted conical spreader mounted in said outwardly flared portion of the penstock; a centrifugal pump mounted in the compression chamber and having its blades disposed opposite the discharge opening in the end of the penstock, the blades of said pump forming channels therebetween, and provided with slots between adjacent channels; a return water pipe from the compression tank to the upper tank; and an air outlet from the compression tank.

11. A hydraulic compressing apparatus comprising a closed compression tank; a penstock extending into the compression tank; means for admitting air to the penstock; a turbine mounted in the compression tank above the normal water level thereof and opposite the discharge end of the penstock and adapted to be operated by the discharge from the penstock; a water outlet from the compression tank; means for supplying Water to the penstock; and an air outlet from the compression tank.

12. A hydraulic compressing apparatus comprising an upper tank; a lower closed compression tank; a penstock extending from the elevated tank into the compression tank; means for admitting air to the penstock; a floatable grill in the upper tank; a guide retaining said grill in floating position above the end of the penstock; a water pipe outlet from the compression tank; means for providing a head of water in the upper tank; and an air outlet from the compression tank.

13. A multi-unit hydraulic compressing apparatus, each unit comprising a closed upper tank; a lower closed compression tank; a penstock extending from the elevated tank into the compression tank; the space above the penstock in the upper tank forming a substantially air tight dome; means for admitting air to the penstock; a return water pipe from the compression tank to the elevated tank; means for returning water to the upper tank through the return Water pipe; and an air outlet from the compression tank communicating directly with the interior of the penstock of the next unit.

14. A hydraulic compressing apparatus comprising an upper tank adapted to contain water, which forms a head; a lower closed compression ter up the return water pipe to the upper tank; 10

and an air outlet from the compression tank.

JOHN E. JONES. ROBERT J. UNSWORTH. 

